Remove multiple calls to free when successively calling jq_reset.
#3134
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Hey, thanks. Possible to add a minimal reuse/reset regression test case to https://github.com/jqlang/jq/blob/master/src/jq_test.c that would be detected by valgrind? |
Sameesunkaria
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Added a separate function for testing the Please let me know if you had something else in mind. :) |
wader
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Please drop the change to gitignore file. Files generated not by the project should not be in per-project gitignore file. |
`jq_reset` calls `jv_free` on the `exit_code` and the `error_message` stored on the jq state. However, it doesn't replace the actual instance of those members. This means that subsequent calls to `jq_reset` will call `jv_free` again on those members, which in turn may call `free` on the same pointer multiple times. Freeing the same pointer multiple times is undefined behavior and can cause heap corruption, which is how I spotted this issue. In practice, this issue only occurs when using a program that may `halt_error`, because that is when the `exit_code` and `error_message` are set to values other than `jv_invalid`. Subsequent attempts to call `jq_start` (which calls `jq_reset` internally) after hitting a `halt_error` can cause you to run into this issue. The changes simply reset the `exit_code` and the `error_message` to `jv_invalid` (the initial value set in `jq_init`) after they are freed.
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Removed the commit with the changes to gitignore |
wader
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Sameesunkaria
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jq_resetcallsjv_freeon theexit_codeand theerror_messagestored on the jq state. However, it doesn't replace the actual instance of those members. This means that subsequent calls tojq_resetwill calljv_freeagain on those members, which in turn may callfreeon the same pointer multiple times. Freeing the same pointer multiple times is undefined behavior and can cause heap corruption, which is how I spotted this issue.In practice, this issue only occurs when using a program that may
halt_error, because that is when theexit_codeanderror_messageare set to values other thanjv_invalid. Subsequent attempts to calljq_start(which callsjq_resetinternally) after hitting ahalt_errorcan cause you to run into this issue.The changes simply reset the
exit_codeand theerror_messagetojv_invalid(the initial value set injq_init) after they are freed.